[PATCH v5 3/5] bnx2x: Eliminate duplicate barriers on weakly-ordered archs
David Miller
davem at davemloft.net
Fri Mar 23 09:43:26 PDT 2018
From: Sinan Kaya <okaya at codeaurora.org>
Date: Fri, 23 Mar 2018 12:31:12 -0400
> Sorry, you got me confused now.
>
> If you look at the code closer, you'll see this.
>
> wmb();
>
> txdata->tx_db.data.prod += nbd;
> barrier();
>
> DOORBELL(bp, txdata->cid, txdata->tx_db.raw);
>
> and you also asked me to rename DOORBELL to DOORBELL_RELAXED() to make
> it obvious that we have a relaxed operator inside the macro.
This still doesn't match the stated pattern.
wmb();
/* no other memory or I/O or IOMEM operation */
writel();
There is a write to a producer index there and then no non-compiler
barrier or any kind before the writel().
So, in fact, it might really need that implicit writel() barrier here!
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